The Permian period is part of the geologic system of classifying geologic formations. It is the last period in the Palaeozoic era. It is preceded by the Carboniferous period and followed by the Triassic period.
Under the dates assigned by uniformitarian geologists, the Permian represents a geologic period from 300 million to 250 million years ago. Its end is defined by the Permian extinction event which is considered to be the largest extinction event the planet has seen, with over 90% of the species alive at that time becoming extinct.
Young Earth creationists reject the uniformitarian assumptions that processes in the world today have always worked in much the same way, so they reject these dates (see geologic system). Instead, they consider most if not all Permian strata were laid during the Great Flood in the time of Noah.